1998 GMC Suburban Owner's Manual - Page 86

To replace the battery: Synchronization Synchronization may be necessary due to the security method used by this system. The transmitter does not send the same signal twice to the receiver. The receiver will not respond to a signal it has been sent previously. This prevents anyone from recording and playing back the signal from the transmitter. To resynchronize your transmitter, stand close to your vehicle and simultaneously press and hold the LOCK and UNLOCK buttons o n the transmitter for at least five seconds. The door locks should cycle to confirm synchronization. If the locks do not cycle, see your dealer for service. Your Doors and How They Work 1. Insert a small coin, or flathead screwdriver, to Side Doors To open the door from the outside, pull the handle LIP and pull the door open. To open the door from the inside, pull the lever toward you and push the door open. separate the bottom of the transmitter from the top. 2. Remove the battery and replace it with a new one, making sure the positive (+) side of the battery is facing down. 3. Snap the top and bottom together. 4. Test the operation of the transmitter with your vehicle. If the transmitter does not work, try synchronizing the transmitter with the receiver.